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Maintenance and RepairMaintenance operations mean the maintenance and inspection of the Nord Stream pipeline system in order to ensure safe and reliable transport of natural gas during the lifetime of the pipeline system by maintaining the certification and in accordance with the requirements of the gas transportation agreement. Nord Stream will have an emergency pipeline repair system in the event of damage to the pipeline. The system will include a repair philosophy, procedures, equipment and material, contracts with vessels and repair companies and agreements with authorities for necessary permits in the different countries and territorial waters. In order to have access to the relevant equipment for subsea repairs Nord Stream maintains membership of the StatoilHydro Repair Club. Regular External Inspection SurveysPlanned survey inspections will be carried out along the length of the pipelines to ensure the integrity of the system. Unacceptable pipeline free spans may develop slowly over time as a result of waves and currents, requiring eventual correction, e.g. by the placement of rocks, sandbags or other supporting structures known as mattresses. Anode potential monitoring will also be performed to ensure the integrity of the corrosion protection system. Inspections will be conducted from a survey vessel equipped with different types of sensors, such as cameras and scanners, to inspect the general condition of the pipelines and to detect potential small leaks. The equipment is typically mounted on remotely operated vehicles, i.e., un-manned, maneuverable underwater robots that are operated from the survey vessel. It will take approximately 60 to 90 days to survey one pipeline. Internal Inspection (Pigging)During operation of the pipeline system, the pipeline will be inspected from the inside by intelligent pigs. Pigs, either individually or in "trains", will be launched from the landfall facilities in Russia and driven through the pipeline by the flow of gas.
At specific time intervals, Nord Stream AG will carry out a more in-depth inspection of the pipeline condition. An "intelligent" pig will be sent through the pipeline system to check for any corrosion or changes in pipeline wall thickness caused by third party impacts. The principle of detection is based on magnetic flux in the longitudinal direction of the pipeline. Additionally, position and geometry (roundness and potential deformations) of the pipeline are measured. Landfall MaintenanceInspection and maintenance activities at the landfall facilities will be done by specialized service contractors on a regular basis, in accordance with law and regulations and best industry practice. These activities are mainly related to instrumentation and control devices and have been considered in the design so that most activities can be safely executed while the pipeline is in operation. However, in case major maintenance work is required to be carried out on the landfall plant equipment, a planned shut down may be required. In order to keep interruptions of gas transport to an absolute minimum, such activities will be scheduled in line with compressor station maintenance and with the demands of the European gas net. Thanks to gas storage facilities as well as the availability of natural gas via multiple other sources any maintenance works of the Nord Stream pipeline system will remain unnoticed by consumers. |
Shortcut: SafetyMore about the safety standards of Nord Stream Paper: LogisticsThe Logistics Concept of Nord Stream |
